Fiber – Your body will tell you what it needs

Everyone talks about fiber and how we need to eat more of it. Our bodies ask for it every day by giving us clues on what kind it needs.  To be honest with you, sometimes when I eat too much fiber, I just don’t feel good.  So, instead of suffering from eating too much, or too little, I’ve decided to do a little research on this carbohydrate (starch) and see if I can figure out what kind of fiber my body is asking for.

The first thing I learned from researching is that dietary fiber is found only in plant foods and amazingly humans don’t have the enzymes to break it down, so really, we can’t digest it.  Whole grains, for example, contain a lot of fiber, which we start to breakdown in our stomachs and small intestines.  But the fiber just passes through to our gastrointestinal tract like a broom to sweep out the digestive tract.  Once it reaches the large intestine, it becomes fermented by our gut microbiome where it turns in to short chain fatty acids (SCFA) that travel through our body, through our blood stream, for energy, or used by intestinal cells.  Although whole grains contain a lot of fiber, fruits, vegetables and legumes (especially Mediterranean diet types) create the best fiber with the most SCFA.

There are two types of fiber, soluble and insoluble.  Each has a benefit in the digestive tract and knowing which type your body needs, can help prevent (or alleviate) unwanted symptoms like diarrhea or constipation.

Soluble fiber attracts water like a sponge and turns to gel during digestion, which slows digestion.  As you can tell from the description, soluble fiber would be good for anyone suffering from diarrhea or loose stools.  Because it slows how fast foods are digested, it can help lower blood sugar, which is a great choice if you battle with diabetes.  It also makes you feel full longer which can aid in weight loss.  This type of fiber is fermented by gut bacteria in the large intestines and provides nutrition to the microbiome.

Examples of soluble fiber foods:

Oats, oat bran, dried beans and lentils, carrots, applesauce, pears, oranges, strawberries, bananas, onions, chickory, sunchokes, avocado, potatoes and sweet potatoes, sunflower seed and brussels sprouts.

Insoluble fiber passes through the gut quickly, which makes it the perfect choice for anyone suffering from constipation.  This type of fiber doesn’t provide the body with nutritional needs or feed our microbiome, but it does keep things moving through the colon and keeps things “cleaned out”.   This type of fiber helps prevent infections of the gut, hemorrhoids, heart disease and may prevent some types of cancers.

Insoluble fiber comes from fruits with skins, uncooked vegetables, nuts and bran, brown rice and whole grain flours and is more rough on intestinal lining than soluble fiber.

Examples of insoluble fiber foods:

Zucchini, broccoli, cauliflower and cabbages, leafy greens, uncooked vegetables, raw peppers, flax and chia seeds, whole grains, fruits with skins and berries, nuts and legumes.

One last thing to keep in mind about fiber.  If you are bloated, have abdominal pain and fatigue after eating fiber, you may want to get tested for something called Small Intestinal Bacterial Overgrowth (SIBO).   SIBO happens when bacteria in the small intestine get out of balance and over grown.  Although there can be almost 1,000 different species of bacteria in our gut, most is meant to be located in the large intestine and colon where they help to breakdown food.  When there is an imbalance in the gut and more bacteria starts to grow in the small intestine, it can create a multitude of symptoms from abdominal pain, bloating and food intolerances to physical pain, fatigue and unexplained vitamin and mineral deficiencies or leaky gut.

As I learned from Dr. Amy Myers article titled 10 Signs You Have Small Intestinal Bacterial Overgrowth (SIBO), the good news is that there are several tests that can diagnose SIBO and it can be treated with dietary change, antibiotics and/or probiotics.   It’s certainly worth mentioning to your doctor if you feel there is an imbalance in your gut from poor diet, overused antibiotics or autoimmune conditions like Chrohn’s disease.

After all this research, the one take away I learned is to increase fiber slowly to prevent your stool from moving too quickly or too slow.  You will also want to drink plenty of water to turn that soluble fiber into the gel consistency that your body needs it to be in to aid digestion and push that insoluble through your digestive tract and through your colon.  Fiber can’t do its job without water, and you don’t want to create and imbalance in the gut, which could lead to other problems like SIBO.  As you can see, the choices of fiber is important to your health so listen to your body, it will tell you what you need.

Allison Webster, R. (2019). Gut Check: Whole Grains and the Microbiome – IFIC Foundation. [online] IFIC Foundation. Available at: [Accessed 1 Mar. 2019].

Mayo Clinic. (2019). How much fiber is found in common foods?. [online] Available at: [Accessed 1 Mar. 2019].

Stop Colon Cancer Now. (2019). High-Fiber Diet Shown To Boost Colon Health. [online] Available at: [Accessed 1 Mar. 2019].

Myers, A. (2019). 10 Signs You Have Small Intestinal Bacterial Overgrowth (SIBO) – Amy Myers MD. [online] Available at: [Accessed 1 Mar. 2019].

BMJ. “High dietary fiber intake linked to health promoting short chain fatty acids: Beneficial effects not limited to vegetarian or vegan diets.” ScienceDaily. ScienceDaily, 29 September 2015. <>.

O’Brien, MS, S. (2019). Top 20 Foods High in Soluble Fiber. [online] Healthline. Available at: [Accessed 1 Mar. 2019].

Decker, F. (2019). Best Sources of Soluble Fiber From Natural Foods. [online] Available at: [Accessed 1 Mar. 2019].